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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/108337] Misaligned memory access issues when inline assembly is used with optimization on x86_64 Date: Sun, 08 Jan 2023 18:56:08 +0000 [thread overview] Message-ID: <bug-108337-4-u2bRmkM7bR@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-108337-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108337 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- int main(int argc, char *argv[]) { int i = 0; char msg[65] = "Hello World 0!\n"; auto result = write(1, msg, sizeof(msg) - 1); i = 0; uintptr_t t; asm("mov %%rsp, %0":"=r"(t)); while (i < 64) { uintptr_t tt = (t >> i) & 0xf; msg[(64-i-1)] = (tt > 9) ? (tt - 10 + 'a') : (tt + '0'); i++; } result = write(1, msg, sizeof(msg) - 1); exit(result >= 0 ? 0 : 1); } Gives: 00000000000000000137fffffffffffeda5b6db6da5a49248124925b7eda5a48 For -static -nostartfiles -nostdlib -Wl,-emain without gives: 00000000000000000137ffffffffffedb6c92480001248137ec8125b6da5a480 You need -mstackrealign to correct for the not aligned stack pointer that the kernel gives.
next prev parent reply other threads:[~2023-01-08 18:56 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-01-08 17:38 [Bug c++/108337] New: " eric-bugs at omnifarious dot org 2023-01-08 17:47 ` [Bug target/108337] " pinskia at gcc dot gnu.org 2023-01-08 18:56 ` pinskia at gcc dot gnu.org [this message] 2023-01-08 21:52 ` eric-bugs at omnifarious dot org 2023-01-08 21:56 ` pinskia at gcc dot gnu.org 2023-01-08 22:20 ` eric-bugs at omnifarious dot org
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